Utilization of shallow geothermal energy in Slovakia focused on ground source heat pump domestic installations / von Jana Mária Obernauer
VerfasserObernauer, Jana Mária
Begutachter / BegutachterinMilics, Gabor
UmfangXII, 116 Bl. : Ill., graph. Darst., Kt.
HochschulschriftWien, Techn. Univ., Master Thesis, 2009
URNurn:nbn:at:at-ubtuw:1-61410 Persistent Identifier (URN)
 Das Werk ist frei verfügbar
Utilization of shallow geothermal energy in Slovakia focused on ground source heat pump domestic installations [7.81 mb]
Zusammenfassung (Englisch)

Geological setting of the Slovak Republic is favorable for occurrence of geothermal energy resources, especially low enthalpy geothermal resources (temperature in the range 20C - 100C). The total amount of thermal-energy potential of geothermal waters in prospective areas (proven, predicted and probable) represents 5 538 MWt. Up to now, the geothermal water is used only for recreation (swimming pools, spa), agriculture (greenhouses heating, fishery) and district heating. The low-enthalpy aquifers suitable for district heating system are limited and available only in regions with specific geological structure. Nevertheless, shallow geothermal resources up to the depth of 400 m are suitable for heat extraction and utilization virtually everywhere. The most geographically extensive use of geothermal energy in the world and the most individual use is ground source heat pump (GSHP) technology which can access the moderate temperatures just beneath the earth's surface. Energy of surrounding accumulated an immense amount of energy in the air, ground or water and represent energy sources which are almost inexhaustible and absolutely free. The heat pump technology required to extract heat accumulated in the air, earth and water has been known for more than a hundred years. The most common heat pump systems, determined by the kind of cooled and heated medium, are: air-to-water, water -to-water, ground-to-water. Due to the fact that shallow ground temperatures are relatively constant, GSHP can be effectively used almost anywhere. The field of application of GSHP commonly comprises the space and domestic water heating to a wide range of building types and sizes. GSHP are particularly suitable for new buildings as well as for older existing buildings, especially in conjunction with reduction of heat demand. The most significant direct benefits of appropriately designed GSHP systems are the reduced energy requirement and the use of a sustainable energy source. In addition, indirect benefits of GSHP systems include low environmental impact with a significant reduction of emissions of COB2B and other pollutants. Slovakia's geological and hydrogeological conditions are very favorable for the installation of GHP water-to-water and earth-to-water systems. This is due to the high average heat flow (78 mW/mP2) compared to the central European average heat flow - the energy yield is in the range of 50 W/m. So far, the number of heat pump installations does not reflect these conditions. It is estimated that at present only app. 100 units of heat pumps are in operation and Slovak GSHP market is still very flat. Barriers to growth in the geothermal heat pump market in Slovakia can be overcome. By far, the most significant one is the high installation cost of GSHP systems. Well-designed incentives could help to overcome the higher installation cost of a GSHP and reduce the payback time to a period comparable with other available RES heating systems. The breakeven point can typically be accelerated by favorable government and utility energy incentives. The most important market barriers to GSHP implementation in Slovakia are definitely limited public awareness and low familiarity with technology on the part of practitioners. Generally, there are a number of misconceptions and myths about GSHP technology mainly due to the unprogressive approach of the authorities. Wider general education would improve the reputation of GSHP and enable misconceptions to be challenged. The presented case study, installation of GSHP system in historical building represent promotion of shallow geothermal technology and challenge social and public opinion that heat pump utilization is predominately applicable only to new and low-energy buildings. The successful implementation of the proposed GSHP system could provide further evidence of the reliability and practicality of utilizing shallow geothermal energy with GSHP despite complicated regional geology, and the official restrictions placed on reconstruction. In combination with building renovation, the implementation of a GSHP system is also feasible for older buildings. Reduction of specific heat demand and the most up to date high efficiency GSHP permits the application of GSHP in bivalent mode with an additional energy source even in historical buildings. This argument is supported by the numerous heat pump installations completed in existing older houses and historical buildings.